You can export your product and inventory data into a CSV file.
Go to Settings > Application Settings > Export Data. You will find this page:
You have the option to choose between Products and Inventory. After you begin your export, we will start generating the CSV file for you. When it is ready, we'll email you with a secure link to download your file.
You also have the option to export a blank template file ("Template Only") if you wish to then import new data into Sellbrite.
There is currently no way to export your Listing data into a CSV file.